Bending a railway line
First apply an array modifier to the train tracks. With a distance set to one, this will make the rail segments touch, and iterate. Then, add a bezier curve. Select it, press tab to switch into edit mode, and then manipulate it to get a good shape. Apply a curve modifier to the rail, and set the object to be the bezier curve you created. The rail will curve to match your bezier curve. An invaluable resource in blender is the modifier encyclopedia on Andrew Price's website. Great tool for reference. Hope this helps!